#142 Equation jumping

Matt Chan

After reading a PDF with hundreds of pages and several hundred equations, I wanted to see if it's possible to implement an equation jumping feature.

For example, if equations are denoted with [ x ] in the document, then mousing over the text "Eqn x shows..." in the document shows a tooltip popup of the text around the first search occurrence of [ x ] (which is presumably the definition).

I'm fairly certain that this situation occurs frequently in mathematical/scientific documentation. In a book, it's simple to flip back and forth, but it's much more distracting to scroll on a laptop to the equation and back to the original page afterwards. I've wanted to implement this in evince, xournal etc for quite a while now, but my time is limited at the moment.

There's several blaring barriers to implementing this and I'm sure Andreas can bring up a few more on the poppler side of things. One would be the different notation for denoting equation numbers. That would likely need to be configured per document. I think it could be set quickly though, and there's probably a prevailing notation in use that we could set as default. I'd appreciate if Dennis or someone else could comment on whether this is true.

Of course, any PDF that doesn't implement a text layer would also be a non-starter. I think most ebooks/journal articles include the text now though.